1. Field of the Invention
The present invention relates to an information distribution system such as a video-on-demand (VOD) system. More particularly, the present invention relates to a system and method for time shifting the delivery of video information to consumers requesting such information.
2. Description of the Background Art
VOD systems providing content encoded according to the various Moving Pictures Experts Group (MPEG) standards are known. For example, a first standard known as MPEG-1 refers to ISO/IEC standards 11172, which is incorporated herein by reference in its entirety. A second standard known as MPEG-2 refers to ISO/IEC standards 13818, which is incorporated herein by reference in its entirety. Additionally, a compressed digital video system is described in the Advanced Television Systems Committee (ATSC) digital television standard document A/53, incorporated herein by reference.
The most important characteristic of a video on demand system is the experience of a user receiving content via that system. That is, a user ideally selects desired content and the system provides the desired content to the user in a timely manner and at a quality level consistent with the user's expectations. Failure to meet the user expectations in terms of image quality, sound quality, system latency or other factors results in a less than satisfying experience to the user.
The practice of “time shifting” within the context of a consumer television experience is commonly implemented by recording consumer-received content using a consumer recording device, such as a video cassette recorder (VCR), video tape recorder (VTR) or other mass storage device. The recorded content is then viewed by the consumer at a convenient time. That is, the time at which the content is view is shifted from the transmission or “live” time to some time in the future.
Unfortunately, present time shifting techniques are extremely limited. For example, the TIVO/ReplayTV techniques allows only a limited storage of information, while VCRs typically allow 2-8 hours of storage, depending upon selected tape speed/resolution. In addition, present consumer-side time shifting techniques require the use of a tuner/demodulator to provide video information to the mass storage device or other magnetic medium. Thus, in the case of a consumer utilizing a single tuner/demodulator to receive content, the consumer cannot simultaneously view and store content from different tuned signals.